Newbie Help - Spots on lower leaves and/or too short?

[DFE87]

HYDRO GROW

Strain - Cluster Bomb - Hybrid 50/50%
# of Plants - 1
Grow Type - Hydro
Grow Stage - Vegetative - 4 weeks since germination
Setup - DWC
Light - 250 Watt CFL 6500k 24hrs a day
Nutrients - Canna Aqua
Medium - Grodan Rockwool and clay pebbles
PH - 5.8
RH - Unknown
Room Temperature -76 to 82
Solution Temperature -76
Room Square Footage - 20
Pests - None Known

Problem:
I'm getting yellow/brown spots develop on the lower leaves, not too bad atm but want to sort it out before it becomes so, also, is it too short? seems very bushy and not sure if correct...
cheers!

 

[Dankbank]

What kind of nuttes are you using and at what ppm? Is it the canna aqua veg a and b? Also tap water or R.o.?

 

[DFE87]

Yeah the Canna Aqua veg a + b and cannazym too,with a water change 5 days ago with 15ml A+B, 25ml Cannazym in 15ltrs using 0 TDS RO water, haven't got anything i can measure the PPM with though...

 

[Dankbank]

Those spots are caused by calcium, magnese, or phosphorus deficiency. It depends on a few things, what water are you using, how often do you adjust your p.H., and it also looks like you have some heat stress going on how far off are your lights? Also how long ago did you transplant into the buckets?

 

[Dankbank]

If you are using the R.O. water you should start adding some some calimag it is a combo of calcium and magnesium wich you lose by running R.O.. Usually after I transplant into my D.W.C. after a couple weeks I will start to get some of that on my lower leaves, I wouldn't start to worry unless it moves on to some of the newer growth. I use General Hydroponics Calimagic and have stopped seeing that happen on my lower leaves. Also what kind of air pump and stones are you using? Do you know the output of your pump?

 

[DFE87]

Transplanted 3 weeks ago, stunted for a week then went crazy, I do weekly water changes with 0 TDS RO water, add nutes then get the PH to 5.8, i also check PH daily it ranges from 5.2 to 6 but may need to calibrate my meter, buffer solution is on its way, the light is only about 8 inches away but top leaves seem fine.... i bought a Ikon DWC pot which came with a hydro air pump... new growth is fine

 

[Dankbank]

I just hopped on to update my journal do before I go I will through this in to, you need to get your light farther away from your plant. The reason that you have those leaves cupping upward is because of heat stress. The temp in your room might be fine but those bigger CFLs are hot and you need to get them off the leaves a little or you are going to end up with some crisp leaves here shortly. A good rule of thumb is put your hand right on top of your canopy and if it is warm on the back of your hand you are to close. Good luck with everything if I get back soon and have some answers on pump and things I might see a couple other problems that you have.

 

[Dankbank]

You are fine for now don't trip on the spots unless it starts to affect some newer growth. Like I said if it does go get some Calimag and you will be alright. That seems far enough away from the light but your leaves are showing signs of heat stress you might want to check it for sure. Do you plan to FIM or Top your plant?

 

[DFE87]

I was going to top it but need to do a little more research on it as unsure when to do it, i was due to start flowering in two weeks but it just seems so short, ill post my daily photo's from day 1 when i get a chance.. and i might do a 50/50 mix of RO and tap next WC, see if that alleviates it a bit..